Improved Focusing of a cosh-Gaussian Laser Beam in Quantum Plasma: Higher Order Paraxial Theory

This paper presents a preliminary study on relativistic self-focusing of cosh-Gaussian (ChG) laser beam and its dependence on the value of decentered parameter b through cold quantum plasma (CQP). In contrast to the earlier work on self-focusing in such a medium, higher order terms in the expansion of the dielectric function and the eikonal have been taken into account. It is seen that the inclusion of such terms (up to r(4)) in the extended paraxial theory does significantly affect the dependence of the beamwidth parameter (f) on the distance of propagation and allows the modification of the shape of the radial intensity distribution. We have also found that ChG in comparison with Gaussian beam has caused better focusing in the CQP, which is very important for some applications in high power laser-dense plasma interactions.